Employee Benefits and Stock Compensation - Summary of Restricted Stock (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Shares granted		297,576	243,391	63,650
Weighted-average grant date fair value		$ 4.66	$ 3.41	$ 2.21
Restricted Stock [Member]
Shares granted		114,331	164,599	123,806
Weighted-average grant date fair value		$ 24.08	$ 16.03	$ 15.03
Fair value of awards vested	[1]	$ 1,407	$ 1,981	$ 836
Restricted Stock Units (RSUs) [Member]
Shares granted		164,268	136,188	127,128
Weighted-average grant date fair value		$ 23.94	$ 13.53	$ 12.63
Fair value of awards vested	[1]	$ 937	$ 846	$ 0

[1] Based on grant date fair value